Boring bars have been used for many years with a fixed cutter projecting radially from a cylindrical bar to finish the cylindrical walls of a bore in a workpiece. Boring bars are also available with one or two adjustable cutters with suitable cutting tips which project radially from a boring bar. Adjustment is desirable to obtain accurate diametrical dimension and also to compensate for tool wear. Where two opposed cutters are used, a balancing of the cutting forces reduces the bending moment on the bar, but it is also important tha each cutter have the same radial dimension to avoid chatter and to equalize the cutting load on the diametrically opposed cutting edges.
Usually the opposed cutters are adjustable simultaneously by a single manually movable part. A problem exists in obtaining the initial positioning of the radial cutters and also in maintaining the position should one cutting edge wear more rapidly than the other.
It is, therefore, an object to provide a boring bar which is relatively simple in design and which permits initial adjustment to equalize the radial positioning of the cutters and which also permits simultaneous adjustment with a fine adjustment which minimizes backlash.
Other objects and features of the invention will be apparent in the following description and claims in which the principles of the invention are set forth together with the manner and process of utilizing the invention directed to persons skilled in the art, all in connection with the best modes presently contemplated for the practice of the invention.